Method of and means for generating electric oscillations



April 27, 1926." 1,582,270

. H. C. 5N OOK ET AL METHOD 70F AND MEANS FOR GENERATING ELECTRICOSCILLATIONS Filed March 18, 1922 Wye/7mm;

flower C 5/200/ 6 5y i 1 a Patented Apr. 27,

UNITED STATES- PATENT OFFICE.

HOKEB O. SNOOK, 01 SOUTH ORANGE, NEW JERSEY, AND JOHN B. JOHNSON, OFEL]!- HUBST, NEW YORK, ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPO-RATED, OF-NEW YORK N. Y., A CORPORATION OF NEW YORK.

METHOD OF AND MEANS FOR. GENERATING ELECTRIC OSCILLATIONS.

Application med March 18, 1922. Serial No. 544,927.

To all whom it may concern:

and JOHN B. JoHNsoN, citizens of the United States, residin at SouthOrange, in the count of Essex, %tate of New Jersey, and at Elmhurst inthe county of Queens, State of New York, respectively, have inventedcertain new and useful Improvements in Methods of and Means forGenerating Electric Oscillations, of which the following is a full,clear, concise, and exact description.

This invention relates to a method of, and means for generating electricoscillations and more particularly to an arrangement for this pur osewhich embodies an electric discharge evice having two elements.

Heretofore it hasbeen proposed to generate electric oscillations byvarying the heating current sup 1y to the cathode of an electricdischarge evice, under the control of the current flowing through anoscillating circuit connected between the electrodes of,

the device. In this arrangement a portion of the current produced in theoscillating circuit is fed back to the cathode heating circii it,whereby the amplitude of the heating current for the cathode and hencethe rate of emission of electrons therefrom are varied in gynchronismwith the oscillations generate By the resent invention a similar resultis obtaine in an entirely different manner. The discharge device isprovided with a cathode current conducting element of relatively larfgephysical dimensions to which a current 0 large amperage is supplied.With large current flow through the conducting element a circularmagnetic field will be set up in the space surrounding the electronemitter or cathode of the device, and the electrons tending to flowacross the s ace, due to the tential difierence su pli between the eectron emitting catho e and the anode, will be deflected at right anglesby this magnetic field and will tend to reenter the cathode. This willincrease the space charge surrounding the cathode and hence increase theimpedance of the device. The larger the current flow through theconductin element the greater is this effect.

n accordan e with this invention a tuned circuit connected between thecathode and dependent of gas ionization.

anode of an electric discharge device is coupled to react upon thecircuit supplying current to the conducting element, whereby thecircular magnetic field surrounding the cathode and hence the deflectingeffect of the field is varied. The space char e and hence the impedanceof the device Wlll be varied synchronously with the fluctuating currentsupplied by the oscillating circuit, and increments of energy will besupplied thereto to maintain it in oscillating condition.

One object of the present invention is to generate oscillationsemploying an arrangement which includes an electric discharge devicehaving an abnormal space charge. Another object of the invention is togenerate electric oscillations by varying the space charge of a twoelement electric discharge device.

The invention itself both as to organization and method of operationwill be best understood by reference to the following descri tion readin connection with the attache drawing, in which Fig. 1 illustrates anoscillator involving the invention; Fig. 2 is a cross-section of thedischarge device shown in Fig. 1; Figs. 3, 3 and 4 illustrate othercircuit arrangements for practicing thediameter and four inches long, ananode one and a half inches in diameter and six inches long, ode shoulpreferably be of the order of twenty amperes. Slpace potential issupplied to the device by t 0 source 6 over a path connecting it withthe cathode 2 and anode 3. The constant current supplied to the cathodeshould so chosen that a ma etic field of the desired value will be puced the current supplied to the cathhaving a tungsten cathode of twentymils within the device, to determine its critical voltage, i. e., thevoltage at which space current will flow, and the potential of thesource 6 should be such that the device operates on that portion of itscharacteristic where small variations in the intensity of the circularmagnetic field produces large variations in the space current. By makingthe sources 5 and 6 adjustable, or using any well known means to secureadjustment of the current supplied by source 5 and the potential of thesource 6 the magnetic field may be controlled. The anode is herein shownas cylindrical in form surroundin the cathode. While this constructionis preferable, it is not essential to the operation of the device ascontemplated by this invention. Included in the space current path is aninductance coil 7 shunted by a condenser 8. The coil 7 is inductivelycoupled to the coil4 included in the supply circuit for the cathode 2.In order to obtain a phase relation between the oscillating current fedback and the space current 1n the device, .Whereby energy may besupplied to the tuned circuit the coils 4 and 7 should be looselycoupled. In this manner the leakage inductance of the coil 4 may madegreat enough to produce a phase difference between the space current andthe oscillate ing current flowing throughthe tuned circuit such thatsustained oscillations may be generated.

As shown in Fig. 2 when current of large amperage is supplied to the hotwire or electron emitter 2 constituting the cathode of the electricdischarge device 1, a circular magnetic field indicated by the arrows asurrounds the wire 2. This field will cause the electrons 12, as theytend to flow radially toward the anode 3, to be deflected in a directionat right angles to the magnetic field and hence tends to force them backto the emitter 2. The'space charge surrounding the electron emitter andhence the impedance of the device will be thereby increased.

The cathode 2 as illustrated in this figure, may consist of a singleelement extending axially of the evacuated vessel or a plurality offilaments, such as are ordinarily used at the present time in electricdischarge devices of well-known construction, may be similarly arrangedand connected in parallel between the terminal contacts of the device.

The anode should preferably be concentric of the cathode and symmetricalthereto. Any unbalance or disturbance which occurs in the tuned circuitwill produce a difference of potential across the condenser 8 and adischarge will take place through the inductance 7 to set uposcillations, the frequency of which will be determined by the constantsof the tuned circuit. By adjusting the inductance 7, condenser 8, orboth, the

constants of thetuned circuit and hence the frequenc ofthe oscillationsgenerated may be varie Due to the coupling between the coils 7 and 4,current variations will be induced in the circuit supplying current tothe cathode, the f r equency of which corresponds to natural period ofthe tuned circuit 7-8. This pulsating current will at one instant aidthe current supplied to the cathode 2 by the source 5 and hence tend toincrease the space charge of the device, and at the next instant willoppose the current normally supplied to the cathode and thereby decreasethe space charge of the device. Obviously, the space charge as wellas'the impedance of the tube will vary at a frequency determined by thetuned circuit 7-8 and by means of the coupling between the coils 7 and17 oscillations of this frequency may be supplied to a load circuit.

In order that sustained oscillations may be produced by the arrangementconstituting this invention it is necessary that the oscillation voltagewave impressed upon the cathode and anode of the device 1, i. e., thespace voltage, should be approximately 180 out of phase with the voltagewave produced in the oscillating circuit. Should the phase angle betweenthe oscillating current produced in the tuned circuit and the pulsationsflowing through the cathode supply circuit be less than that necessaryto maintain oscillations, an adjustable inductance or variable condensermay be used, whereby the phase relation between these two waves may beadjusted. As shown in Fig. 3, the coil 7 is coupled to the coil 4 bymeans of acoupling circuit 911- 13,'the last mentioned being a variablephase adjusting inductance. In case it is desired to give the Wave fedback a leading characteristic relatively to the space current, avariable condenser 14 may be included in a coupling circuit, as shown inFig. 3*.

From the preceding description it willbe seen that by using a twoelement electric discharge device having an electron emitting cathode oflarge current carrying capacity and supplying it with a constant currentof large amplitude, a circular magnetic field is produced which servesto increase the space charge of the device. By properly selecting theamplitude of the current supplied to the cathode, the space charge ofthe device under normal conditions may be definitely determined and byproducing an oscillating current and impressing it upon the cathode, themagnetic eld w iich determines the space charge of the device will becaused to vary synchronously therewith. Increments of energy wi lltherefore be supplied to the oscillating circuit and as a resultsustained oscillations will be generated.

lln

lit

Although inthe preceding description ,inde endently of electronemission. l-

.'positioned interiorly ot the cathode and symmetrical with reference:to both the cathode and anode.

In F ig. 4 there is shown an evacuated vessel 1 enclosing. angauxiharyconductor- ..,1 8,"a cathodeQ and an anode 3. A source sup lies heatingcurrent to the cathode 2 an also adjustable current of largeai'nplitudei-to-.the auxiliary conductor 18, through a coil/t, Thecurrent of large amplitude supplied'to the auxiliary conductor 18 servesto produce a constant circular magnetic field in the space between thecathode 2 and anode 3 within the; dis-- charge device. I

Space current 1s, suppl ed to the discharge device bya source (3 througha path extending from the positive terminal of the source 6 to the anode3 across the space to the cathode 2 and through a coil 7 to the negativeterminal of the source. The coil 7, which is adjustable, is shunted by avariable condenser 8 to constitute a frequency determining circuit. Coil7 is inductively associated with the coil 4- included in the energizingcircuit for the auxiliary conductor 18.

As in the arrangements previously de scribed either the inductance 7 orcondenser 8, or both, may be varied to regulate the frequency of theoscillations generated.

Except for the fact that the oscillating current is fed back through thecoupling 7& to the energizing circuit of the auxiliary conductor 18 tovary the magnetic field within the device in synchronism with theoscillating current generated, this system operates in the same manneras the arrangements previously described.

In its broad aspect this invention is adapted to provide an arrangementwherein the space charge of an electric discharge device, including acathode adapted to emit electrons independently of gas ionization and ananode, may be increased by establishing a circular magnetic field in thespace between the cathode and anode thereof by current flowing through aconductive element within the device and cyclically modifying themagnetic field to vary the space charge and hence the space currentflowing between its electrodes.

The discharge device described above is of general application and maytherefore be used as-an amplifier, repeater, current regulator, voltagecontroller, relay or rectifier.

\Vhile a particular circuit arrangement I and specific details have beenset forth for the purpose of completely disclosing the invention, it isto be understood that this invention is not limited thereto, but only bythe scope of the appended claims.

\Vhat is claimed is:

1. The, method of operating a space discharge-device havingelectron-cmitting and receiving, electrodes and an additional electrodewhich comprises producing within the device, by current flowing throughthe additional electrode, a charge for controlling the low of electroniccurrent.

The method of operating a space discharge device having an electronemitter, an anode and an additional electrode. which comprises producingin the space between the emitter and anode, by current flowing throughthe additionalelectrode, a magnetic field which controls the flow ofelectron currcnt within the. device.

3. The method of opc'ating a space discharge device havingelectron-emitting and receiving electrodes and an additional electrode,which comprises producing within thc device, by current flowing throughthe additional electrode, a circular magnetic field for controlling theflow of electronic current.

4. The method of operating a space discharge device havingelectron-emitting and receiving electrodes and at least one otherelectrode, which comprises producing within the device, by currentflowing through the other electrode, a charge which determines theritical voltage of the device.

5. The method of operating an electron discharge device having anelectron-cmitting cathode, an anode and an additional electrode, whichcomprises causing to flow through the additional electrode a current ofamplitude large compared to that required to produce e'ectrou emissionfor establishing within the device a charge determining its criticalvoltage, and varying said charge.

6. A method of operating a self-oscillating system comprising anelectron discharge device having an elcctron-cmittcr. an anode and atleast. one other electrode. and circuits associated with said device,which comprises supplying to said other electrode a current of amplitudesutiicicntly large to establish within the device a charge whichdetermines its critical voltage. generating oscillations in theassociated circuits, and cyclically varying said charge by saidoscillations.

7. An electron discharge device having an electron-emitting cathode, ananode and an additional electrode adapted to carry a current of suchvalue as to create a magnetic field strong enough to cause electrons todeflect in curved orbits located in planes which pass through the axisof the cathode,

7 between the cathode and anode.

" ing its critical voltage,

.8. An apparatus for amplifying a variable electric current com risingan electron discharge device in accordance with claim 7, an inputcircuit including the additional electrode and an output circuitconnected in series with the cathode and anode.

9. An oscillation enerator comprising an electron discharged eviceincluding an electron emitter, an anode and an additional electrode,means for supplying to said additional electrode a current for producingwithin the device a magnetic field determining its critical voltage,means external to said device for determining the frequency of theoscillations enerated, and means for cyclically contro ling saidmagnetic field.

10. An oscillation generator comprising an electron discharge deviceincludln an electron emitter, an anode and an additlonal electrode,means for supplyin to said addi tional electrode a' current E01producing within the device a magnetic field determinmeans external tosaid device for determining the frequency of the oscillations generated,and means for.

cyclically varying the currents supplied to said additional electrode.

11. An oscillation generator comprising an electron discharge deviceincluding an electron emitter, an anode and an additional electrode,means for supplying to said additional electrode a current for producingwithin the device a magnetic field determining its critical voltage,means external to said device for determining the frequency of theoscillations generated, and means controlled b said oscillations forcyclically varyin the magnetic field.

12. in electric discharge device including an electron emitter, an anodeand a current energized means within said device for roducing in thespace between said emitter and anode a magnetic field determining thecritical voltage of the device, and means for cyclically varying themagnetic field.

13. An oscillation generator comprising an electron discharge devicehaving arcathode, an anode and "an additional electrode, means forcausing to flow through said additional electrode a current ofsufficient amglitude to produce a controlling field for the ischargebetween the anode and the cathode,

between said cathode and anode a circular magnetic field determining thecritical volt age of the device, means for producing oscillations,provided with frequency determining means, included in the circuitconnecting the cathode and anode; and means for varying the magneticfield by said oscillations.

15. An oscillation generator comprising electric discharge deviceincluding an electron emitter, an anode, and a current conductive means,means for supplying to said conductive means a current suflicient tocontrol the electron emission, an oscillation circuit externalto saiddevice for determining the frequency of the oscillations generated, andmeans controlled by said oscillations for varying the am litude of thecurrent supplied'to said con uctive means.

16. An oscillation enerator comprising an electric discharge devicehaving a oathode, an anode and a current conducting means, means forsupplying heating currentto said cathode and for supplying to said tit?conducting means energizing current of amplitude large compared to thatsupplied to the cathode, a circuit connecting said cathode and anodeincluding a frequency determining circuit, and means for coupling saidfrequency determining circuit to the means for supplying energizingcurrent to said conducting means.

In witness whereof, we hereunto subscribe our names this 16th day ofMarch JOHN B. JOHNSON. HOMER O. SNOOK.

